The immediate goal of these studies is to develop methods for efficiently introducing human globin genes into hemopoietic cells both from tissue culture lines and normal bone marrow. Such techniques will enable the further characterization of important globin gene regulatory sequences including those involved in stage and tissue specific expression. To test the feasibility of using a viral vector for gene transfer we have constructed a hybrid SV40 virus which contains the prokaryotic gene coding for chloramphenicol acetyl transferase (CAT)- an enzyme readily detected by sensitive and specific enzyme assay. With this vector we have obtained gene transfer and transient expression in a large number of fibroblast and hemopoietic cell lines of both mouse and human origin and in normal fresh bone marrow cells of mouse, monkey and man. The results with suspension hemopoietic cell lines and fresh bone marrow cells represent a significant advance over the low or undetectable levels of gene transfer obtained with the CaPO4 precipitate technique. Based on these results we are constructing other recombinant SV40 vectors containing another positive selectable marker gene (neomycin resistance) the human Alpha globin gene and the human Epsilon globin gene respectively. Such viral vectors will be used to attempt cotransformation with a selectable gene and a human globin gene of both hemopoietic cell lines in vitro and normal hemopoietic stem cells in vivo.